The present is directed to the field of grenades, and more specifically to a safety fuze for use with hand grenades.
The hand grenade presently in use by the U.S. Department of Defense is the M2l3, shown in FIG. 11 and U.S. Pat. No. 2,562,928 to Lewis. The hand grenade fuze 100' incorporates a number of features standard in hand grenades and similar, hand thrown, fuze-activated devices. For example, a pull ring assembly 700' is inserted through the lever 600', through apertures in the fuze body 100', over the striker assembly 500' to restrain the striker assembly 500' in the safe position. Also, a safety clip 800' is fastened around the lever 600' and an extension 232' of the fuze body 200' to prevent accidental, premature release of the lever 600' and the striker assembly 500' if the pull ring assembly 700' was accidentally removed.
However, in military situations when silence is of the utmost importance, the user frequently employs the unauthorized, unsafe, procedure of removing the safety clip 800' to avoid detection by the enemy given by the distinctive sound from its removal, or the noise it produces upon impacting objects after being discarded. Also, because of the short length of the striker assembly 500', if the lever 600' is unknowingly released even a slight amount after the pull ring assembly 700' is removed, the striker assembly 500' will be allowed to rotate and the striker 530' will hit the primer 320', initiating the firing sequence. As this can occur without the knowledge of the user, the grenade can function while still in the user's hand or attached to an article of clothing.
Most fuze assemblies for hand grenades and the like employ lever and striker assemblies similar to those of the M213. Examples of such assemblies are disclosed in U.S. Pat. No. 2,042,461 to Gibson et al.; U.S. Pat. No. 2,421,672 to Short; U.S. Pat. No. 2,911,9l3 to Suden; and U.S. Pat. No. 4,513,667 to Caruso.
Another safety problem encountered with the M2l3 is associated with the firing train assembly, i.e., the primer assembly, the delay charge/cavity, and the detonator assembly. In the M213, the detonator charge is in direct fluid communication with the delay charge/cavity in the fuze body stem, and the delay charge/cavity is in direct fluid communication with the primer assembly. An insufficient amount of delay charge can cause a grenade to function, after the firing train has been initiated, in a shorter time than that required of complete delay charge. Also, the absence of any delay charge in the delay cavity can cause an instantaneous functioning of the grenade after the firing train has been initiated. Also, a crack or cracks, or porosity having fluid communication between the interior stem cavity and the outer stem wall of the fuze body, can permit hot gasses to be in like fluid communication with the interior of the detonator assembly. Also, the through fluid communication within the components of the firing train can cause deterioration of the explosive or pyrotechnic components, shortening shelf life and endangering the user who is depending on reliable performance of the device.
Other fuzes for hand grenades employ primer, delay, and detonator assemblies similar to those of the M2l3, as shown by U.S. Pat. No. 4,383,470 to Assman.
It is the solution of these and other problems to which the present invention is directed.